Wal-Mart Stores Inc., the world’s largest retailer, has confirmed to the Chicago Tribune that despite protests from environment and food-safety advocates, it will not restrict sales of genetically modified corn in its stores.

The corn will not be labelled and consumers will not be notified that the sweet corn they are buying are engineered by agro-giant Monsanto and genetically-altered (GMO stands for genetically modified organism) to resist the toxic impact of being sprayed with chemical pesticides and herbicides.

“A lot of people who were their customers explicitly said we don’t want you to carry this product, and I think it’s unfortunate that they chose not listen to that feedback,” said Patty Lovera, assistant director of Food & Water Watch. The consumer group had submitted a petition to Wal-Mart with 463,000 signatures, she said.

Consumer advocates argue that too little research has been done on to be certain of the effects such products can have on those who eat or them, but say certain troubling health trends correspond to the rise of GMO foods in the marketplace. At the least, they argue, such products should be labeled so consumers are aware of what they’re purchasing.

“How would you ever know if there are adverse health effects?” said Michael Hansen, a senior scientist at Consumers Union, the policy arm of Consumer Reports. “There has been a doubling of food allergies in this country since 1996. Is it connected to genetically engineered foods? Who knows, when you have no labeling? That is a problem.”

Earlier this year, Whole Foods, Trader Joe’s and General Mills said they would not carry or use the genetically modified sweet corn.

In California this year, a state referendum is up for a vote that would require all GMO products to be labelled so that consumers are aware if modified ingredients are contained in the products they buy. The chemical pesticide companies and companies like Monsanto are fighting hard against the measure, fearing that if California, the country’s most populous state, passes such a sweeping consumer protection laws other states will likely follow.